Double Olympic champion Laura Trott today accused cyclists of being reckless and causing accidents by failing to obey the rules of the road.

The cycling gold medallist said she was shocked by how many rogue riders jumped lights and dangerously weaved through traffic — and added that accidents were “not always the car’s fault”.

The star also insisted that laws must be brought in to make safety helmets compulsory for all riders as she spoke of how her sister, also a professional cyclist, had survived being knocked off her bike by wearing such a helmet.

The London 2012 champion spoke out on rider behaviour using the strongest terms yet in her role as the chief ambassador for the Mayor, who has expressed concern that cycling’s image is being tarnished by an aggressive, Lycra-clad minority.

She told the Standard: “Cyclists wonder why they get a bad name. I see cyclists jumping in and out of the buses and people wonder why they get hit.

“It’s not always the car’s fault. Cyclists need to help themselves and should not jump red lights. I would ride in London but I certainly wouldn’t ride like that, you just have to be careful. I can understand going down the outside of traffic but you should obey the rules of the road because we’re all road users.”

Fourteen cyclists were killed on London’s streets last year and already there have been six deaths this year.

But City Hall says the streets will become much safer as Boris Johnson’s £913 million cycling fund is spent on schemes including a “superhighway” along the Embankment, linked to Amsterdam-style quiet roads in outer boroughs.

Accident blackspots such as major road junctions and roundabouts will benefit from bike-friendly measures.

Trott said the new infrastructure, which has escaped major government cuts, was overdue. She added: “It shows show we’re becoming a cycling nation and the scheme is needed now. If you don’t do it then London’s roads are going to be filled with cyclists. We need more bike lanes in central London.”

But Trott, 21, from Essex — who won gold in the Omnium and team pursuit events in the velodrome — called on politicians to go further and make helmets a must for cyclists.

It puts her and fellow cycling superstar campaigner Sir Bradley Wiggins at loggerheads with the Mayor’s cycling commissioner Andrew Gilli- gan, who insists that helmets have no proven benefits and refuses to wear one, ruling him out of this summer’s RideLondon 100 event.

Trott said wearing a helmet was drummed into her at a young age by her parents, despite complaints that it was “uncool”.

In 2010 her sister, Emma, 23, broke her collarbone and suffered concussion so bad that she “barely even knew who she was” when a car hit five British riders in Belgium.

Trott believes that Emma’s life was saved by the helmet she wore. She said: “When I was 11 I didn’t want to look uncool but my parents wouldn’t let me out unless I was wearing it.

“I think it should be a legal requirement to wear a helmet. So many lives have been saved by them and it saved my sister’s life. She got hit by a car and cut her head open.

“When Emma called from hospital she barely even knew who she was, so if she wasn’t wearing a helmet now she wouldn’t be here today.

“For me, putting my helmet on now is a habit and I’ll wear it even if I’m going to the shop for a pint of milk.”

Trott spoke after being announced as an ambassador for the Lee Valley VeloPark, which includes the Olympic velodrome.

Paralympic gold and double silver medallist Mark Colbourne was also announced as an ambassador for the park, which will open to the public in March.

It includes a BMX track, mountain bike trails and a road cycling circuit.